In recent years, a display device including a self-luminous element such as an electroluminescence (EL) element has been developed. The display device is widely used by taking advantage of thinness, lightweight and so on due to the high quality, wide view angle and unnecessity of backlights because of the self-luminous characteristic.
However, in a self-luminous element, characteristics such as intensity may be deteriorated from the initial states, which may cause dark spots having partially low intensity and shrinks having intensities deteriorating from ends of display screens. These problems are due to deterioration of light emitters, which is caused by the invasion of water and/or oxygen to an exposed insulator and the extension of water and/or oxygen to the light emitters with the passage of time.
Furthermore, in recent years, the pattern forming by droplet discharge technique has been applied to the flat panel display field and has been actively developed. Droplet discharge technique has many advantages including unnecessity of a mask for direct rendering, easy application to a large substrate and a high use efficiency of materials. Thus, droplet discharge technique has been applied for producing an EL layer, a color filter, and electrodes for a plasma display (As disclosed in “T. Shimoda, Ink-jet Technology for Fabrication Processes of Flat Panel Displays, SID 03 DIGEST, pgs. 1178-1181”).